It seems that it may have started. Experts have predicted a global pandemic of a new fatal flu for so long we have become inoculated against the horror of the concept. Now in Mexico a new form of flu has arisen, from swine rather than from birds, and is spreading from person to person. So far, it is believed that around 100 people have died out of around 1000 suspected cases. Worryingly, in common with previous pandemic flu outbreaks (as opposed to “normal” seasonal flu) this seems to be causing worse illness in young and healthy people. Some cases have been reported in other countries also. In the 1918 outbreak 500 million were infected (40 per cent of the world’s population at the time) and 50 million died.